The Immune Reconstitution Group at Duke University Medical Center (DUMC) studies the patho-physiology of and mechanisms of immune reconstitution for inherited and acquired immunodeficiencies, including severe combined immunodeficiency (SCID), DiGeorge syndrome, acquired immunodeficiency syndrome (AIDS), and myeloablation for cancer. This diverse group of eight investigators within the Departments of Medicine, Pathology, Pediatrics and Surgery, is requesting a FACSVantage(TM) SE flow cytometer with TurboSort(TM) Plus high- speed cell sorting to replace an aging FACStarPlus(TM) flow cytometer to support 19 ongoing, NIH-funded, clinical research projects. No high- speed cell sorters are currently available at Duke. While three slower, older cell sorters (including the instrument being replaced) are available, they are not capable, nor state-of-the-art for performing the applications of this group of investigators who will require approximately 95% of the total usage of the instrument. Access to the instrument will be made available to other users based upon the advice of an internal advisory committee. The instrument will be integrated into the core facilities of the Duke Human Immunology Core Facility and the Duke Specialized Center of Research (SCOR) in Rheumatoid Arthritis (RA). Continued financial support for the operation and maintenance of the instrument will be provided by the Bone Marrow Transplantation Program, and a charge- back mechanism. The instrument will have a single, well-trained operator. In summary, the Immune Reconstitution Group at DUMC has a demonstrated need and is requesting support for a state-of-the-art FACSVantage(TM) SE flow cytometer. Advisory committees, institutional support, financial support for continued maintenance and management plans are in place to insure that the instrument will be fully and appropriately utilized.